Hard disk drives are used in almost all computer system operations. In fact, most computing systems are not operational without some type of hard disk drive to store the most basic computing information such as the boot operation, the operating system, the applications, and the like. In general, the hard disk drive is a device which may or may not be removable, but without which the computing system will generally not operate.
The basic hard disk drive model was established approximately 40 years ago and resembles a phonograph. That is, the hard drive model includes a plurality of storage disks or hard disks vertically aligned about a central core that spin at a standard rotational speed. A plurality of magnetic read/write transducer heads, for example, one head per surface of a disk, is mounted on the actuator arm. The actuator arm is utilized to reach out over the disk to or from a location on the disk where information is stored. The complete assembly, e.g., the arm and head, is known as a head gimbal assembly (HGA).
In operation, the plurality of hard disks is rotated at a set speed via a spindle motor assembly having a central drive hub. Additionally, there are channels or tracks evenly spaced at known intervals across the disks. When a request for a read of a specific portion or track is received, the hard disk drive aligns a head, via the arm, over the specific track location and the head reads the information from the disk. In the same manner, when a request for a write of a specific portion or track is received, the hard disk drive aligns a head, via the arm, over the specific track location and the head writes the information to the disk.
Over the years, refinements of the disk and the head have provided great reductions in the size of the hard disk drive. For example, the original hard disk drive had a disk diameter of 24 inches. Modern hard disk drives are generally much smaller and include disk diameters of less than 2.5 inches (micro drives are significantly smaller than that).
The recording or read/write heads of modern hard disk drives do not actually make contact with the recording media. Rather the heads “fly” on a cushion of air generated by the relative motion of the head over a rapidly spinning platter or disk comprising the recording media. The ability of a head to fly at a desirable height is a critical performance aspect of hard disk drives. Such flying heads are generally referred to or known as “sliders.” As recording density increases, the slider flying height, e.g., the distance between a slider and a recording media surface, generally decreases. Such decreases in flying height typically require ever flatter slider surfaces. A lapping process typically determines a flatness characteristic of a slider.
A wafer is a basic “building block” upon which numerous processing actions take place to produce multiple components. Wafers also form a similar building block for the production of magnetic read and/or write heads (“sliders”) as used in hard disk drives. The production of such devices can comprise many different processing steps. It is not uncommon for hundreds of operations to be performed on wafers to produce magnetic heads.
In recording head technology, the volume or size of the recording sensor is very small. For example, modern recording sensors are of the order of 100 nm. Typically, such sensors become ever smaller with successive generations of hard drive technology. In general, such heads are so small that each sensor has unique signal and noise characteristics due to individual microstructure, milling and lapping surface conditions. For example, removing a few nanometers of material from a reading sensor during a lapping process can dramatically affect various operational characteristics of a head, e.g., resistance, signal amplitude and/or signal to noise ratio.
In a conventional head manufacturing process, a head or set of heads is lapped to establish surface quality and a target sensor stripe height. Unfortunately, lapping to a well controlled target stripe height produces an undesirably broad distribution of amplitude and drive performance results from such conventional head manufacturing processes.
Accordingly, there is a need for systems and methods for manufacturing magnetic heads. Additionally, in conjunction with the aforementioned need, systems and methods for manufacturing magnetic heads that account for unique signal and noise characteristics of individual magnetic heads are desired. A further need, in conjunction with the aforementioned needs, is for manufacturing magnetic heads in a manner that is compatible and complimentary with existing magnetic head processing systems and manufacturing processes.